In the early years of the 20th century, Leo Stein, his younger sister Gertrude, his older brother Michael and his sister-in-law Sarah, recently arrived in Paris from the United States, cornered the market of contemporary art by Pablo Picasso, and to a lesser extent by Henri Matisse. Incredible though it may be, the history of Cubism was written on the walls of Leo and Gertrude’s rue de Fleurus studio, while Matisse’s development could be traced at the Paris home of Michael and Sarah on rue Madame and then in their large Le Corbusier-built mansion near Paris.